* {
    margin: 0;
    padding: 0;
    overflow: hidden;
}

#background {
    position: fixed;
    left: 50%;
    top: 50%;
    transform: translate(-50%,-50%);
    width: 100vw;
    height: 100vh;
}

#mainBody {
    position: fixed;
    right: 12.5%;
    top: 50%;
    transform: translateY(-42.5%);
    width: 35vw;
    height: 80vh;
    border-radius: 1vw;
    border: 0.3vw solid #6699CC;
    background-color: rgba(255, 255, 255, .6);
}

#tabBar {
    display: flex;
    position: fixed;
    right: 4vw;
    top: 4vh;
    width: 50vw;
    height: 5vh;
    /* background-color: chocolate; */
}

.item {
    height: 100%;
    line-height: 5vh;
    flex-grow: 1;
    text-align: center;
    border-left: 2px solid black;
}

#tabBar .item:nth-of-type(1) {
    border-left: none;
}